1. Field of the Invention
The present invention relates generally to coaxial cable connectors, couplings and fittings such as barrel connectors. More particularly, the present invention relates to socketed, female-type coaxial fittings adapted to establish a proper ground when coupled to male connectors. Known prior art is classified in United States Patent Class 439, Subclasses 497, 578, 851, and 852.
2. Description of the Related Art
Popular cable television systems and satellite television receiving systems depend upon coaxial cable for distributing signals. As is known in the satellite TV arts, coaxial cable in such installations is terminated by F-connectors that threadably establish the necessary signal wiring connections. The F-connector forms a “male” connection portion that fits to a variety of socketed receptacles, forming the “female” portion of the connection. Barrel connectors, for example, have a pair of female terminal ports, one on each end, and they join two F-connector borne cables together. F-connectors have numerous advantages over other known fittings, such as RCA, BNC, and PL-259 connectors, in that no soldering is needed for installation, and costs are reduced as parts are minimized.
For example, with an F-connector, the center conductor of a properly prepared coaxial cable fitted to it forms the “male” portion of the receptacle connection, and no separate part is needed. A wide variety of F-connectors are known in the art, including the popular compression type connector that aids in rapid assembly and installation. Hundreds of analogous connectors are seen in U.S. Patent Class 439, particularly Subclass 578.
However, the extremely high bandwidths and frequencies distributed in conjunction with modern satellite installations necessitates a variety of strict quality control factors. For example, the electrical connection established by the F-connector must not add electrical resistance to the circuit. It must exhibit a proper surge impedance to maintain a wide bandwidth, in the order of several Gigahertz. Numerous physical design requirements exist as well. For example, connectors must maintain a proper moisture seal against the environment, and they must function over long time periods through extreme weather and temperature conditions. Requirements exist governing frictional insertion and disconnection or withdrawal forces as well.
Importantly, since a variety of coaxial cable diameters exist, it is imperative that satisfactory F-connectors function with differently sized cables, such as RG-6 and RG-59 coaxial cables that are most popular in the satellite television art.
The foregoing F-connector considerations relate directly to the structure of the “female” sockets or receptacles to which the F-connectors are fitted. The “female” half of the junction must compliment the F-connector design imperatives. High bandwidth must be maintained through the junction, and reliable and effective impedance control is necessary. The socket, for example, must not exhibit an impedance discontinuity that can effect bandwidth. Electrical continuity is imperative.
Common receptive sockets to which F-connectors are fitted typically include some form of coaxial tube disposed therewithin into which the innermost conductor of the coaxial cable (i.e., that forms the “male” end of the connection that projects outwardly from the front of the F-connector) is inserted. A proper electrical contact must be formed at the latter juncture, internally of the mated connector elements. A variety of design constructions have been proposed for insuring such a connection.
For example, U.S. Pat. No. 4,128,293 issued Dec. 5, 1978 provides enhanced connections with an elongated, metallic band having a plurality of substantially parallel fingers. One end of each finger is attached to and integral with the band. The fingers provide a large surface area for electrical contact.
U.S. Pat. No. 4,447,108 issued May 8, 1984 discloses an improved socket for electrical connectors defined by twisting of a cylindrical inner sleeve. Slots arranged on the cylindrical surface of the sleeve are inclined with respect to the longitudinal sleeve axis. The shape of the slots contributes to correct sleeve deformation in response to twisting.
U.S. Pat. No. 4,550,972 issued Nov. 5, 1985 discloses a formed contact socket with circumferentially continuous rings at pin receiving ends for enhancing electrical contact, and a second circumferentially continuous ring at its inner end. An intermediate portion of the socket comprises beams which have ends integral with the rings. Inwardly formed spherical bosses are provided on the rings which engage a pin upon movement of the pin into the socket. The bosses are spaced along the axis of the socket and are encountered sequentially during axial movements of the pin into or out of the receptive socket.
U.S. Pat. No. 4,750,897 issued Jun. 14, 1988 discloses a contact apparatus with at least one segmented body formed by bars separated from each other by slots and having a curved central area. The bars have the form of a three-dimensional curve. In their end areas, the bars possess a section curved in the opposite sense to said curved central area.
U.S. Pat. No. 4,840,587 issued Jun. 20, 1989 discloses a female contact that receives a pin contact from an F-connector. Areas establishing electrical contact with the pin contact upon insertion are arranged at least approximately according to a family of straight generatrices of a hyperboloid of revolution of one branch. The composite female contact comprises a proper elastic contact element consisting of a cylindrical sleeve provided with through slots on its surface and inclined with respect to the longitudinal axis of the sleeve, which is deformed by twisting according to a predetermined angle and directed in the sense of inclination of the slots.
U.S. Pat. No. 5,667,409 issued Sep. 16, 1997 discloses a barrel connector for use with F-connectors that includes a pair of opposite “female” ends. A tubular, center conductor tube for coaxial cable including plural, inwardly punched contact points defined on the tube ends. The contacts firmly abut the central wire of coaxial cable terminating in an F-connector. The tube is constrained within a larger diameter housing with spaced sleeves. The material of the holes is punched inward but is not removed from the tube forming the contact component such that a pair of inclined planes extend toward the interior of each end of the tube.
U.S. Pat. No. 5,863,226 issued Jan. 26, 1999 discloses a connector for coaxial cable including a tubular contact fitted between two insulative sleeves. The contact member is made from sheet material by curling. Ends of the contact member are not joined together, and a narrow slit is defined between them. When a wire core with a diameter between 1.2 to 1.3 mm, i.e., as with an F-type coaxial connector, is inserted into the contact member, the contact member is stretched open to achieve greater resilience.
U.S. Pat. No. 6,113,431 issued Sep. 5, 2000 provides an F-port coaxial barrel connector. The connector body comprises threads on its opposite ends for receiving F-connectors, and a hexagonal nut formed in between, with a flat sections lathe-fabricated at the outer extremities of the aforesaid threads and a containment hole extending lengthwise through the center of the connector body. Fitted inside the containment hole is a first insulator sleeve and a second insulator sleeve, and clipped in between the first and second insulator sleeves is a tubular contact component. The utilization of lathe fabrication allows for a smooth and even finish on all flat surfaces and enables the assembly of the first insulator sleeve, the second insulator sleeve, and tubular contact component to be conveniently inserted into the containment hole, while also preventing dislodging from the containment hole.
U.S. Pat. No. 6,065,997 issued May 23, 2000 discloses an analogous connector device for use with cable and satellite television installations, including an integrally formed housing, a contact member and an insulative tube fitted in an inner through hole of the housing. An arch annular groove is formed on an inner edge of one end of the housing and an engaging flange is formed at the other end of the housing. The insulative tube is disposed with an arch annular flange. The contact member is placed in the insulative tube which is fitted into the housing with the annular flange engaged with the annular groove. Two ends of the housing are formed with plane connecting faces, whereby the tightly connecting area with the connector is increased without a gap so as to effectively isolate interference by various kinds of free waves.
U.S. Pat. No. 6,808,426 issued Oct. 26, 2004 also discloses a barrel connector for use with popular F-connectors. A conductive contact tube that is coaxially constrained within the connector by special end sleeves includes inwardly bent, clamping tabs for establishing electrical contract by grasping the coaxial cable center conductor when an F-connector is threadably fitted to then barrel connector.
U.S. Pat. No. 6,899,563 issued May 31, 2005 provides a coaxial cable connector with an internal transmission tube comprising four elastic strips at each of its two ends. The four elastic strips are disposed in the transmission tube in a bent manner, and each elastic strip is formed with a projecting plane and inclined planes. Side edges of the four elastic strips are joined to form a clamping end for inserting and connecting an axis of a coaxial cable therein.
U.S. Pat. No. 7,252,560 issued Aug. 7, 2007 discloses a center conductor for use in a coax jack module. The center conductor has a conductive body with a crimped region within one of a first half and a second half of the conductive body, that is defined by slots. Numerous other patents relating to electrical construction contact techniques exist, such as U.S. Pat. Nos. 3,317,887, 3,381,261, 3,678,451, 3,815,081, 3,861,776, 4,002,400, 4,298,242, 4,550,972, 6,186,841, 7,121,881, 7,387,548, and 7,442,080.
In our prior U.S. Pat. No. 7,931,509 an improved center tube construction for use with barrel connectors was disclosed. The improved center tube establishes contact with male connectors, nominally F-connectors. The elongated, generally tubular contact tube was mechanically fixed in position at the coaxial center of the connector. At least one female juncture for receiving a male coaxial connector was included. The contact tube, preferably made of copper beryllium alloy, includes radially spaced apart, curved slots and strips forming a polygonal enclosure whose sides dependably abut the center conductor of coaxial cable emanating from a F-connector coupled to at least one end of the connector.
Despite efforts in the industry to provide reliable, wide-band connectors and accessories, problems often result where connectors are improperly installed. Existing threaded connector designs rely on proper installation techniques. For example, it is well recognized that the F connectors must be properly tightened when installed. In other words. F-connectors must be properly torqued to create a proper ground connection. Threaded F-connector nuts should be installed with a wrench to establish reasonable torque settings. Critical tightening of the F nut to the threaded female socket or fixture applies enough pressure to the inner conductor of the coaxial cable to establish proper electrical connections. A dependable electrical grounding path must be established through the connector body to the grounded shield or jacket of the coaxial cable.
Known barrel connectors depend heavily on the application of proper torque during installation. The common instillation technique is to torque the F-connector with a small wrench during installation. Absent proper application torque, the electrical grounding path can be compromised and can become intermittent. In some cases installers only partially tighten the F-connector. Some installations are only hand-tightened. In any case, resulting electrical pathways with typical known female connector designs are easily compromised when application torque is improper.